Production of high molecular weight phenolic substances from coal



Patented May 31, 1938 UNITED STATE PRODUCTION OF HIGH MOLE CULAR WEIGHT PHENOLIG SUBSTANCES FROM COAL Leo Kasehagen, Pittsburgh, Pa., assignor to Carnegie Institute of Technology of Pittsburgh,

Pa., Pittsburgh, Pa., sylvania a corporation of Penn- No Drawing. Application May 13, 1937,

Serial No. 142,429

16 Claims.

My invention relatesto the treatment of coal whereby there is produced a high molecular Weight phenolic substance. I have found that valuable products, phenolic in nature, are obtained by heating coal, preferably crushed to 16 to 20 mesh (Tyler standard screen scale) with an aqueous solution of an alkali metal hydroxide at a suitable temperature in a closed pressure vessel lined with a suitable material, such, for example, as nickel or silver, which will resist the action of the hot alkali. The phenolic substances are found in the solution. 1

Both the amount of the phenolic material formed and its composition depend upon the temperature at which the treatment takes place and the concentration of the solution used during the alkali treatment. In the case of Edenborn coal, some material of phenolic nature is formed at all temperatures in the range from 250 to 400 Cl'when an alkali metal hydroxide such as sodium hydroxide or potassium hydroxide is used, but

the amounts are appreciable only at temperatures ranging from 275 to 350 C. The following table, in which the yields of the phenols are calculated on a dry, ash-free basis, illustrates the trend of yields with variations in the temperature of treatment.

Yield percent of EEG gym, dry, ash-iree coal (using treatment NaOH 5N) Alkali con- Percent yield of centration phenolic material 0. 1 N l. 2 1. 0 N.- 11. 0 5.0 N 6. 9 l0. 0 N. 1. 3 l5.0N 0.8 60. 0 %l 1. 2 i 80. O 0. 8 100.0 0.7

The above tables show that a temperature of the order of 275-350 C. is the optimum temperature of treatment for Edenborn coal and the optimum alkali concentration ranges from about 0.1 to 5 N. 7

The change in composition of phenolic material with change in the temperature of the treatment is shown in the following table. All treatments were made with 5 N NaOH:

period of treatment need not exceed approximate- 1y 5 hours. The following table gives the rates of production of phenolic substances when 50 grams of Edenborn coal are treated with 5 N sodium hydroxide at about 325 C.:

Rate of producfi'fgg g tion of phenolic hours substances in grams per hour This table shows that the reaction starts at high velocity, but decreasesin velocity rapidly with the passage of time so that the reaction is esentially complete at the end of approximately 5 hours. It has also been observed that certain phenolic substances can be produced by merely heating to a reaction temperature and allowing to cool.

The phenolic material produced by the alkali treatment when sodium hydroxide is used as the alkali is in the form of soluble sodium salts of the phenols and these salts are removed from the vessel in which the reaction was carried out along with the alkali solution. The salts may be precipitated from the alkali solution by neutralizing with acid or by saturating with carbon dioxide, the latter methodiindicating that the material is phenolic rather than acidic. An additional indication of the phenolic nature of the material is afforded by the fact that methylation, which maybe brought about by either dimethyl sulphate or diazomethane, results in a product which cannot be hydrolyzed by the use of a boiling alkali solution. l

The high molecular weights of the phenolic material are indicated by the fact that they are amorphous solids, cannot be distilled without decomposition even in a vacuum, and are completely insoluble in the common organic solvents, with the exception of methanol and acetone, in which they are only slightly soluble. So far as I know, fused catechol is the only organic solvent in which they dissolve completely. Apparent molecular weights determined cryoscopically in this solvent range from 218 to 242 but the physical qualities are not at all consistent with such low molecular weights so that these figures undoubtedly represent the size of the building unit of the phenol rather than the size of'the phenol molecule as it exists in the solid state. Equivalent weights obtained by methylation and determination of methoxyl content were of the same order of magnitude as the molecular weights determined in catechol.

It is not feasible to set forth all the conditions necessary for the formation of the phenolic products from all coals, but the optimum conditions can readily be determined experimentally for any coal by' following the teachings of this invention.

While I have described the preferred form of my invention, it is to be understood that various modifications in the details thereof maybe made,

without departing from the spirit of the invention, which is not to be limited other than as in the appended claims.

I claim:

1. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal with an aqueous solution of an alkali metal hydroxide, and precipitating the substances from the solution.

2. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal with an aqueous solution of sodium hydroxide, and precipitating the substances from the solution.

3. In the treatment ofbituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal with an aqueous solution of potassium hydroxide, and precipitating the substances from the solution.

4. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal at a temperature between 250 C. and 400 C. with an aqueous solution of an alkali metal hydroxide, and precipitating the substances from the solution. a

5. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal at a temperature between 250 C. and 400 C. with an aqueous solution of sodium hydroxide, and precipitating the substances from the solu tion.

6. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal at a temperature between 250 C. and 400 C. with an aqueous solution of potassium hydroxide, and precipitating the substances from the solution.

7. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal with an aqueous solution ranging from about 0.1 N to 99% of an alkali metal hydroxide, and precipitating the substances from the solution.

8. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal with an aqueous solution ranging from about 0.1 N to 99% of sodium hydroxide, and precipitating the substances from the solution.

9. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal with an aqueous solution ranging from about 0.1 N to 99% of potassium hydroxide, and'precipita'ting the substance's from the solution.

10. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal at a temperature between approximately 250 C. and 400 C. with an aqueous solution ranging from about 0.1 N to 99% of an alkali metal hydroxide, and precipitating the substances from the solution.

11. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal at a temperature between approximately 250 C. and 400 C. with an aqueous solution ranging from about 0.1 N to 99% of sodium hydroxide, and precipitating the substances from the solution.

12. In the'treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heatingthe coal at a temperature between approximately 250 C. and 400 C. with an aqueous solution ranging from about 0.1 N to 99% of potassium hydroxide, and precipitating the substances from the solution. 1

13. In the treatment of bituminous coal forthe production of high molecular weight phenolic substances, the steps. comprising heating the coal at a temperature between approximately 250 C. and 400 C. with an aqueous solution ranging from about 0.1 N to 99% of an alkali metal hydroxide for a period up to about 6 hours, and precipitating the substances from the solution.

14. In the treatment of bituminous coal for the production of high molecular weight phenolic substances, the steps comprising heating the coal at a temperature between approximately 275 and 350 C. with an aqueous solution ranging from about 0.1 N to 5 N of an alkali metal hy- I droxide, and precipitating the substances from the solution.

15. A high. molecular weight phenolic substance which is obtained by treating bituminous coal at a temperature between 250 and 400 C. with an aqueous solution ranging from about 0.1 N to 99% of an alkali metal hydroxide.

16. A phenolic substance having apparent molecular weights ranging from 218 to 242 and whose actual molecular weights are a multiple of the apparent molecular weights, which is ob tained by treating bituminous coal at a temperature between 250 and 400 C. with an aqueous solution ranging from about 0.1 N to 99% of an alkali metal hydroxide.

LEO KASEI-IAGEN. 

